“…Finite element methods (FEMs) have become a popular tool for the dynamic analyses of complex structures. Various forms of elements such as shell element combined with beam element (Hota and Chakravorty, 2007), axisymmetric elements (Al-Najafi and Warburton, 1970; Raj et al., 1995), hierarchical finite elements (Bardell and Mead, 1989a,b), super shell elements (Mustafa and Ali, 1987a; Jiang and Olson, 1994), stiffened elements (Sinha and Mukhopadhyay, 1994; Samanta and Mukhopadhyay, 2004), semi-loof and facet shell elements (Mustafa and Ali, 1987b), isoparametric elements (Palani et al., 1992; Nayak and Bandyopadhyay, 2002a,b), semi-analytical finite elements (Stanley and Ganesan, 1997) and curved triangular shell elements (Pany, 2003) have been used to capture the vibratory characteristics of stiffened shells or panels. A spectral finite element model of the periodically stiffened shell was developed by Solaroli et al.…”